The present invention relates to a polyarylate and a preparation process thereof, and more particularly to a polyarylate suitable for use as a reactive polymer, which is mixed with another polymer to give a polymer alloy or as a precursor used for obtaining a block copolymer, and a preparation process thereof.
It has hitherto been known that polyarylates are excellent in heat resistance, mechanical strength, dimensional stability, transparency, optical properties, and the like. Therefore, they have widely used as motor vehicle parts, electronic or electric parts, and the like.
It has been known that the polyarylates are prepared by condensation reaction of aromatic dicarboxylic acids or their derivatives with bisphenols or their derivatives. According to the known preparation methods, the obtained polyarylates have carboxyl group or hydroxyl group as a functional thermal group. Also, according to the known methods, for controlling the molecular weight, or the carboxyl group content or the hydroxyl group content of the polyarylate, phenol or p-(t-butyl)phenol is used as an agent for controlling the molecular weight.
As polyarylates into which a functional group other than carboxyl group and hydroxyl group is introduced, the following polyarylates have hitherto been known. For instance, Japanese Unexamined Patent Publication No. 50-48097 or No. 60-137925 discloses that for improving the hydrolysis resistance and thermal stability, amide group is introduced into the polyarylate at the polymer ends. Japanese Unexamined Patent Publication No. 61-130335 discloses a polyarylate having dimethylmaleimide group at the polymer ends which is used as a material used for preparing a film capable of increasing the molecular weight under an electromagnetic field, and a preparation process thereof. Japanese Examined Patent Publication No. 63-36336, No. 63-36337 or No. 63-36338 discloses a polyarylate having an unsaturated group at the polymer ends which is used as a reactive oligomer and a raw material for coatings.
The above-mentioned publications disclose a technique wherein the stability of the polyarylate itself is improved, a technique wherein the molecular weight of the polyarylate is increased and a technique wherein the functional group is introduced into the polyarylate for giving the reactivity to the polyarylate with a compound or a polymer capable of conducting addition reaction such as radical reaction. According to these techniques, therefore, it cannot be expected that the polyarylate reacts with a polar group such as amino group, hydroxyl group or an acid anhydride group. Accordingly, it is strongly desired to obtain a reactive polyarylate which can be used as a reactive polymer capable of reacting with an oligomer or a polymer having the above-mentioned polar group to give a polymer alloy or which can be used as a precursor of a block copolymer.
An object of the present invention is to provide a polyarylate which is useful as a reactive polymer used together with another polymer to give a polymer alloy or as a precursor of a block copolymer.
Another object of the present invention is to provide a preparation process thereof.
These and other objects of the present invention will become apparent from the description hereinafter.